The invention relates to a process for treating tobacco stems to increase their filling capacity, and specifically to a method of cutting and conditioning said tobacco stems to obtain cut stem sections that are generally uniform in size.
The art of treating tobacco stems by some form of cutting to produce stem sections having generally uniform size suitable for use as filler material and smoking articles is well known in several variations. Thus, U.S. Pat. No. 3,734,104, discloses a process for treating tobacco stems wherein the tobacco stems are first rolled or crushed prior to being cut to filler size. This particular method suffers from the disadvantage that the rolling or crushing procedure tends to destroy the fiber structure of the tobacco stem, and also results in the production of tobacco stem sections that vary widely in length. Also, as the cut tobacco stem sections are frequently subsequently expanded by steam treatment or the like, the destruction of the fiber structure that occurs from the rolling treatment tends to cause undesirable variations in the extent of expansion of the stem sections.
U.S. Pat. No. 3,556,112 discloses a method for treating tobacco stems which comprises initially expanding or puffing the stems, and subsequently cutting the puffed or expanded stems in a cutting direction parallel to the direction of the stem fibers. This method, like that of the '104 patent, is deficient in that the preliminary expansion treatment likewise causes the destruction of the fiber structure of the stems and weakens the stems such that a quantity of particulate material or dust is developed when the stems are subsequently cut. The resulting stem sections are therefore frequently non-uniform in size and the development of dust from the cutting operation detracts from the usable filler material obtained from the treatment process.
Finally, U.S. Pat. No. 4,076,030 discloses a method for the treatment of tobacco stems which comprises first treating the stems with water to add moisture thereto, followed by cutting the stems in a direction perpendicular to the longitudinal axis of the stem, which is disclosed in the patent to develop improved expansion over cutting techniques which rely on longitudinal cutting direction. This method, like those described earlier, however, is deficient in that it results in stem sections that are non-uniform in length and thickness and therefore less desirable for use as filling material in smoking applications.